1. Field of the Invention
The present invention relates to a heat history control system and to a printer and, more particularly, to a heat history control system for a thermal print head and to a printer using the heat history control system.
2. Description of the Related Prior Art
Conventionally, a thermal printer which performs printing by using a thermal print head has been used. To maintain print quality in the thermal printer, it is necessary to perform heat history control for the thermal print head. An example of the heat history control for the thermal print head is disclosed in Japanese Laid-Open Patent Publication No. HEI 4-146158.
In a small-size thermal printer to be mounted on, e.g., a POS apparatus or the like, it is frequently performed to select a low-performance and low-cost microprocessor or lower the capacity of a memory such as a RAM or ROM for the purpose of cost reduction. As faster printing and higher print quality are pursued, however, it is difficult in most cases to obtain satisfactory performance with these structures. To satisfy the demands, it is an essential requirement to externally provide a special-purpose printing control circuit and minimize a process performed by the processor. FIG. 1 is a block diagram showing a prior-art technology, in which a heat history control circuit 144 is provided in a thermal print head interface LSI 104. However, the provision of a special-purpose printing control circuit leads to the problems of a complicated structure and increased cost.